Method of and means for forming filamentary articles



June 25, 1946. A. 0. RYAN METHOD OF AND MEANS FOR FORMING FILAMENTARYARTICLES Filed June 19, 1945 m 5mm W W $w 5Q 53%. E NE W a m E y V F m ar r w m a Y B N. IIIIIIH NIH SE WWW QSQQ IMM MMW MM# 11111 QST N atentedJune 5, i946 METHOD OF AND MEANS FOR FORMING FILAMENTARY ARTICLES qAlbert 0. Ryan, River Edge, N. J. v Application June 19, 1943, SerialNo. 491,476

Claims. 1

This invention relates to methods of and means for forming filamentaryarticles, and more par-v ticularly to the continuous formation ofthreadlike structures from liquids which may be hardened by a change intemperature or by chemical reaction.

An object of this invention is to provide a novel method and means forforming filamentary articles.

Another object of this invention is to continuou'sly form threads fromliquid temperaturehardenable materials discharged within a moving streamof heated material.

A further object of this invention is to continuously form threads orfilaments by discharging a fluid, heat-hardenable material within amoving stream of heated material flowing at the same speed as the speedof the heat-hardenable material.

An additional object of this invention is to form continuous threads bydischarging a fluid material within a moving stream of another fluidmaterial flowing at the same speed as the discharged material andhardening the latter in this stream by chemical reaction.

A specific object of this invention is directed to a novel method andmeans for producing latex thread.

These and other objects and advantages of thepresent invention willbecome apparent from the following description of a preferred examplethereof, illustrated in the accompanying drawing wherein:

Fig. 1 is a schematic view, with certain portions in enlargedcross-section, illustrating a preferred form of apparatus according tothe present invention; I

Fig. 2 is an enlarged, partial cross-sectional view of part of theapparatus illustrated in Fig. 1;

Fig. 3 is a transverse cross-sectional view taken along the line ofIII-III of Fig. 2; and

Fig. 4 is a transverse cross-sectional view showing a modified form ofthe apparatus illustrated in Fig. 2.

In the example illustrated in Fig. 1, there is shown a long tube l0which may be formed of glass or other material suitable for the liquidto be contained therein. The inner diameter of the tube Ill will dependupon the size of the thread to be formed, but in any event willpreferably be relatively small compared to its length,

which may be from twenty to forty feet and depends upon the timerequired to coagulate the inner fluid. In a preferred form, one end ofthe tube I0 is formed with an enlarged section forming a chamber I2 towhich is connected an inlet pipe I4. Inside of the chamber l2 andpreferably projecting partially into the pipe I0 is a nozzle [6 whichmay also be made of glass. The nozzle I6 is preferably slidably mountedin an extension I8 formed integrally with the walls of the chamber l2,while a rubber sleeve 20 grips the outside of the projection l8 andabout the nozzle I6 to hold the latter in place in the position desired,and at the same time prevents leakage of fluid from the chamber l2.

In the example given for the formation of latex thread, the chamber l2and the pipe ID are filled with hardening fluid such as glycerine underconstant pressure from a container 22 supplied from the conduit 24. Inorder to maintain a constant head within the container 22, the

latter may be formed with an overflow pipe 26 which may discharge anyexcess fluid back into a sump 28 (through suitabl connectin ipes notshown). The glycerine is pumped into the container 22 through theconduit 24 by means of a pump 30 supplied from the sump 28, and isheated in assage by means of any suitable apparatus indicated at 32.

' The liquid latex is supplied from a suitable container 34 throughasiphon 36 and an intermediate connecting hose 38. In order that the flowof the liquid latex may be accurately controlled, the container 34 maybe suspended by a sprin 4| which is so designed that as the latex leavesthe container 34 the spring 40 will contract such an amount as to keepthe head of the latex supply constant. Likewise, as more latex is addedto the container from time to time the sprin 40 will expand so as tomaintain the head in this container constant relatively to the p itionof.

the nozzle l6.

In accordance with the present-invention, it will accordingly be seenthat heated glycerine flowing from the container 22 fills the chamber l2and then flows outwardly through the tube II) to the sump 28. Thediameter of the tube Ill is such that under the pressure contemplatedthis tube will remain substantially completely full of the glycerineuntil just near the far end thereof. At the same time, liquid latexfrom-the container 36 flows through the nozzle l6 where it is firstpre-heated by the glycerine 40 surrounding the portion of the nozzle inthe container l2, and is then discharged from the end of the nozzle intothe moving stream of glycerine. Since, in accordance with the presentinvention, it is contemplated that the relative pressures of latex andglycerine in the containers 34 and 22 are such that in the pipe in thetwo will flow at the same speed, the latex discharged into the stream ofglycerine will be carried along in the center of the glycerine as acontinuous enclosed semiliquld thread which, under the combined actionof heat and the dehydrating action of glycerinc, gradually coagulatesinto a solid continuous filament 42. This solid thread or filament isthen drawn out from the far end of the tube by means of pulling rollersH, and is then passed to a suitable cooling and washing bath (notshown). The heating device 32 will remove any water from the sump 28,and the recovered glycerine may be reused as described.

The manner in which the stream .;of glycerine 40 enclosed and carriesalong the latex thread 42 may be more clearly understood from a study ofFigs. 2 and 3. The glycerine, being relatively viscous, will tend todrag along the inner surface of the tube and the relative speeds ofmovement within the tube may be represented by the curve A, which showsthat this stream will move relatively slowly near the inner surface ofthe tube, and more rapidly over a small cross-sectional area at thecenter, which is the section into which the latex is discharged by thenozzle Hi.

This stream-lined flow of the glycerine is known as viscous flow andprevents the mutual diffusion of miscible liquids or the mixing ofnon-miscible liquids of low viscosities. Thus, so long as the dischargespeed of the latex from the nozzle I6 is the same as the speed of themoving stream of glycerine at this center area, the glycerine will carrythe latex along without breaking or stretching it. Since the innerdiameter of the two ends and the diameter of the discharge nozzleopening l6 can be accurately measured, the desired constant speed canreadily be obtained and determined by the relative fluid pressures ofthe glycerine and of the latex. Such pressures are then maintainedconstant, as by the devices for producing constant head illustrated, bysuitable proportional pumps, or other means known in the art.

The apparatu is applicable for producing threads of any cross-sectionalshape, determined by the formation of the discharge nozzle opening l6,provided only that the inner cross-sectional area of the tube I isshaped proportionately to the cross-section of the desired thread. InFig. 4, for example, I have shown on an exaggerated scale, a flat threadH2 in a stream of glycerine I40 contained within a tube H0. The tube H0,in this case, i so proportioned that the speed of the central area ofglycerine which surrounds the thread |42 is constant and the same as thedischarge speed of the latex from the nozzle l6. As will be seen from astudy of Fig. 2, by way of comparison, this constant area or core willbe found at a section equally spaced from the inner walls of thecontainer. Thus, if the constant speed core is to have an irregularcross-section, the inner walls of the container must have substantiallysimilar shape. Other forms of thread than that shown in Figs. 2, 3, and4, are, of course, contemplated, and are possible if the principles ofthis invention are followed.

While it has been found advantageous in the formation of latex thread topro-heat the latex by means of a pre-heating chamber l2 surrounding aportion of the nozzle IS, in certain instances and in the case of theformation of threads of other materials, such pro-heating may not benecessary and the chamber can be eliminated. In this case. the nozzlewill project into the tube l2 just beyond the point at which the fluidis introduced, and at a point at which flow within the tube has becomestream-lined.

As an example of the method of forming latex thread according to theaforedescribed invention, it may be mentioned that thread one-hundredthof an inch in diameter has been formed within a tub having an internaldiameter of one-quarter of an inch, with the glycerlne heated to 160 to212 R, which will cause a pre-heating of the latex to about F. withinthe nozzle l6 before its discharge. This causes a slightde-stabilization of the latex which, when it comes into contact with thehot glycerine, soon forms a continuous latex thread.

Instead of using glycerlne to harden the latex by the combined action ofheat and dehydration, the latex may be hardened chemically bydischarging a stream of alkaline-stabilized latex into a stream of anaqueou external fluid of low pH. The external stream could be a solutioncontaining bufier salts such as magnesium sulphate, zinc-ammoniasulphate, and the like, or an acid solution such as acetic acid, formicacid, and the like. In all cases, however, the shape of the thread to beformed is maintained by the equilibrium forces of the stream-linedviscous flow.

Variations in the details of the apparatus which will occur to thoseskilled in this art are contemplated and are included as part of thepresent invention provided, however, that in all cases the liquidthread-forming material is discharged into a stream-lined flowing fluidflowing at the same core speed as the discharged thread-formingmaterial. Instead of heating the glycerine before it i pumped into thecontainer 22, it is, for example, possible to heat the glycerinedirectly either when it is in the chamber I! or when it is in the tubel0, as the case may be. The tube l0 may be vertical, as well ashorizontal.

As previously stated, the materials from which the apparatus are madewill depend upon the characteristics of the material forming the threadand of the confining coagulating or otherwise hardening material. It isaccordingly contemplated that, in accordance with the principles of thepresent invention, other threads than latex thread can be formed. Forexample, artificial thread-forming resins or plastics may be dischargedinto a movin stream of material and there condensed, polymerized orchemically interacted, as the case may be. Likewise, with similarsuitable apparatus, molten metal may be discharged into a stream ofcooling material and carried therealong until it become suitablyhardened for withdrawal. It will thus be apparent that in accordancewith the principles of my invention, substantially anytemperature-hardenable or chemically-hardenable material may be used,provided it is supported within a suitable medium flowing with viscousflow; a temperature-hardenable liquid may be defined as a y liquidsolution or colloid which is in a normally liquid state but which wouldbecome hardened or coagulated at an elevated temperature, or, to put itmore simply, any liquid which can be changed to a substantiallypermanent hardened condition by a temperature elevation. For bestresults in forming a round thread it is desired that the interfacialtension be as high as possible, but surface tension is not thecontrolling factor.

Therefore, while I have, for the purposes of I illustration, shown anddescribed one particular form of apparatus for carrying out my method inconnection with the formation of one type of thread or filament, it isto be understood that the invention is not limited to the one specificexample given. but only as set forth in the objects and the claims whichfollow.

I claim:

1. The method of forming continuous threads, which comprises the stepsof discharging a relatively viscous liquid into a relatively small tubeat such a speed that the liquid flows inthe tube with viscous flow,discharging a relatively thin continuous liquid stream of thread-formingmaterial into the center of the stream of relatively viscous liquid andat substantially the same speed and in the same direction as saidviscous liquid, whereby said stream of viscous liquid supports saidthread-forming material at its center, causing the thread-formingmaterial to solidify while supported in the center of the stream ofviscous material, and then withdrawing the solidified material from theviscous liquid in the form of a thread.

2. The method of forming continuous threads, which comprises the stepsof discharging relatively viscous liquid into a relatively small tube atsuch a speed that the liquid flows in the tube with viscous flow,discharging a relatively thin continuous liquid stream oftemperature-hardenable thread-forming material into the center of thestream of relatively viscous liquid and at substantially the same speedand in the same direction as said viscous liquid, whereby said steam ofviscous liquid supports said thread-forming material at its center,creating a temperature diflerence between the thread-forming materialand the viscous liquid while the former is supported in the center ofthe stream of the latter suflicient to harden said material, and thenwithdrawing the hardened material irom the viscous liquid in the form ofa. thread.

3. The method of forming continuous threads, which comprises the stepsof discharging a relatively viscous liquid into a relatively small tubeat such a speed that the liquid flows in the tube with viscous flow,discharging a relatively thin continuous liquid stream of thermo-settingthread-forming material into the center of the stream of relativelyviscous liquid and at substantially the same speed and in the samedirection as said viscous liquid, heating said liquid to a temperaturesuflicient to harden said material whereby said stream of viscous liquidsupports said thread-forming material at its center, and saidthread-forming material is hardened while still supported by the heatedviscous liquid, and then withdrawing the hardened material from theviscous liquid in the form of a thread.

4. The method of forming latex threads, which comprises the steps ofdischarging a stream of glycerine into a relatively small tube at such aspeed that the glycerine flows in the tube with viscous flow,discharging a relatively thin continuous liquid stream of latex into thecenter of the stream of glycerine and at substantially the same speedand in the same direction as the stream of glycerine, heating saidglycerine sufiiciently high to coagulate said latex whereby saidglycerine supports said latex at its center and the latter is coagulatedby the heating of the former while so supported, and then withdrawingthe heat-coagulated latex from the glycerine in the form of a relativelyfine thread.

5. The method of forming latex threads, which comprises the steps ofdischarging a stream of relatively viscous buffer solution having a pHvalue sufliciently low to agglomerate latex into a relatively small tubeat such a speed that said solution flows in the tube with viscous flow,discharging a relatively thin continuous stream of alkaline liquid latexinto the center of the stream of buffer solution and at substantiallythe same speed and in the same direction of flow as said solution,whereby said stream of bufier solution supports said stream of liquidlatex at its center and the latter is agglomerated by the former whileso supported, and then withdrawing the agglomerated latex thread fromthe bufier solution in the form of a relatively flue thread.

ALBERT 0. RYAN.

